From: "kstephens (Kurt  Stephens)" <redmine@...>
Date: 2012-08-09T09:31:43+09:00
Subject: [ruby-core:47085] [ruby-trunk - Feature #6841] Shorthand for Assigning Return Value of Method to Self


Issue #6841 has been updated by kstephens (Kurt  Stephens).


If we want lexical multiplicity to equal evaluation multiplicity...

Should:

  obj.foo.bar[baz.daz] .= to_i

behave as?:

  begin
    temp1 = obj.foo.bar
    temp2 = baz.daz
    temp1[temp2] = temp1[temp2].to_i
  end

... Since the following evaluates "obj.bar.baz" and "baz.daz" only once:

  class Obj
    def foo
      puts "#{self}#foo"
      @foo ||= Foo.new
    end
  end
  class Foo
    def bar
      puts "#{self}#bar"
      @bar ||= { }
    end
  end
  class Baz
    def daz
      puts "#{self}#daz"
      :x
    end
  end
  obj = Obj.new
  baz = Baz.new
  obj.foo.bar[baz.daz] = 1

... Similarly for below:

  obj.foo.bar[baz.daz] ||= 1


----------------------------------------
Feature #6841: Shorthand for Assigning Return Value of Method to Self
https://bugs.ruby-lang.org/issues/6841#change-28739

Author: wardrop (Tom Wardrop)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 2.0.0


=begin
Quite often in Ruby, I find myself doing something like: (({my_var[:foo][:bar] = my_var[:foo][:bar].to_i})) or (({obj.foo.bar = obj.foo.bar.to_i})). Realising this, I thought of what would be a fairly nice shorthand syntax for this, which could be: (({my_var[:foo][:bar] .= to_i})). How this works should be pretty self-explanatory. The (({.=})) operator works exactly like any other assignment operator of this nature.

Would be nice to see this in Ruby 2.0. Wondering what others think of this?
=end


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